Enzymatic treatment of pulp for lyocell manufacture

ABSTRACT

Bleached and unbleached pulps are treated with an enzyme in one or more stages of the bleaching process to yield a low DP pulp suitable for lyocell manufacture. This allows higher throughput of fiber an economy of manufacture.

FIELD

This application relates to the reduction in the degree ofpolymerization (DP) of cellulose with enzymes to provide a pulp withacceptable metals levels suitable for lyocell manufacture.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a 1 K magnification of a lyocell fiber spun from the low DPpulp in this application.

SPECIFICATION

In order to obtain a higher throughput in lyocell production (higherconcentration of pulp in the solvent NMMO or higher throughput per holeper minute) it is necessary to use a lower DP pulp than currently used.Use of enzymes at various stages of the bleaching process can yieldlower DP pulps which are suitable for lyocell.

Enzymes are used in the treatment of cellulosic pulp to improve thebleaching and to reduce the DP of the pulp. One use of enzymes is tocontrol the viscosity of the pulp during the bleach treatment. A lowuniform viscosity is needed for dissolving and non dissolving pulpsuseful for rayon or lyocell production. Enzymes may be used to controlthis viscosity.

Enzymes that are useful with cellulose include xylanases, cellulases,hemicellulases, peroxidases, mannases, laccases (oxidoreductases),lipases and combinations of these enzymes.

The cellulose pulp must be at the correct pH in order for the enzymes towork. The usual pH is 3 to 10. An acids such as sulfuric, nitric orhydrochloric acid, is usually used to adjust to the appropriate pH butthere are problems associated with the use of these mineral acids. Themineral acids tend to harden the outside of the cellulose fibers andreduce the void volume within cellulose pulp fibers thus make it moredifficult for the enzymes to interact with the cellulose pulp fibers.Mineral acids are applied as a liquid and the dispersion of the acidthrough the pulp can be non-uniform.

Carbon dioxide can be used to adjust the pH of the cellulose pulp fiberto the correct pH of 2 to 7.5 and does not create the problems that theuse of mineral acids do. The carbon dioxide tends to maintain theopenness of the cellulose pulp fiber or biomass and allow betterinteraction of the enzyme with both the outside and the inside of thecellulose pulp fiber or biomass. The carbon dioxide is applied as a gasand tends to disperse more uniformly throughout. Other organic acidssuch as acetic acid can also be used.

Various bleaching sequences can be used to make non dissolving pulp forlyocell. It is important that during the bleaching sequence that copperlevels and total transition metals be kept low since this elementadversely affects the NMMO which is used to dissolve the cellulose.

It has now been found that lyocell pulps with a low DP and suitable forlyocell production can be produced by the use of enzymes after oxygendelignification (before bleaching), intermediate in the bleachingsequence or alternatively at the end of the bleaching sequence. In oneembodiment the bleaching sequence is OXDE_(p)D where O is oxygendelignification stage, X is the enzyme treatment stage, D is thechlorine dioxide stage, E_(p) is the caustic extraction stage in thepresence of peroxide and D is the bleaching stage with chlorine dioxide.In another embodiment the bleaching sequence is ODE_(p)DX where O isoxygen delignification, D is bleaching with chlorine dioxide, E_(p) iscaustic extraction in the presence of peroxide, D is chlorine dioxidebleaching and X is enzyme treatment. In yet another embodiment thebleaching sequence is OXDE_(p)DX where O is oxygen delignification X isenzyme treatment, D is bleaching with chlorine dioxide, E_(p) is causticextraction in the presence of peroxide, D is chlorine dioxide bleachingand X is enzyme treatment. Treatment of an unbleached kraft pulp with anIV of 6.2 and a Kappa of 28 to 30 using one of these bleach sequences,for example OXDE_(p)D, can reduce the pulp to an acceptable D. P. range,and the pulp has an acceptable copper number and acceptable totaltransition metals levels.

Unbleached pulp with an IV (intrinsic viscosity) from 10 to 5 dl/g canbe contacted in a bleaching sequence with at least one stage of anenzyme treatment and reduce the pulp by 8 to 2 units. The enzymetreatment can also occur after the bleach sequence or alternatively theenzyme treatment can be in the bleaching sequence and after the bleachsequence.

In one embodiment the pulp is reduced to 2 to 4 IV units; in anotherembodiment the pulp is reduced to 2.5 to 3.5 units.

In one embodiment the enzyme is added at 0.045 to 4.5 kg/MT pulp. Inanother embodiment the enzyme is added at 0.136 g to 3.27 kg/MT pulp Inyet another embodiment the enzyme is added at 0.227 g to 1.36 kg/MTpulp.

The term “degree of polymerization” (abbreviated as DP) refers to thenumber of D-glucose monomers in a cellulose molecule. Thus, the term“average degree of polymerization”, or “average DP”, refers to theaverage number of D-glucose molecules per cellulose polymer in apopulation of cellulose polymers. DP and IV were determined by ASTM1795-96.

EXAMPLE 1

Pulp with a Kappa of 28 to 30 from the normal Kraft process underwent anoxygen stage delignification with H₂O₂ and sodium extraction at 121° C.(250° F.) to obtain unbleached pulp with an IV of 6.2 dl/g ( FallingBall or FB of 86). This pulp was washed (POW, post oxygen washer) andthe POW 3^(rd) stage wash had an initial set point of 68° C. and stockexit pH of about 7 (CO2 adjusted), the pulp with the adjusted pH wastreated with cellulase Biotouch C700 from Ashland Inc. (AB Enzymes)added at POW standpipe at a dosage of 0.45 kg/MT with a retention timeof about three hours to lower viscosity the viscosity to an intrinsicviscosity (IV) of 5.5 (FB of 50) for DE_(p)D bleaching. This bleachedpulp (DE_(p)D) had an intrinsic viscosity (IV) of 3.2 dl/g when takenfrom the couch trim (control sample in Table 1). This was the startingmaterial for more treatment (Tables 1 to 5).

In one embodiment pulp with an IV of 6.2 dl/g is treated with an enzymeafter the oxygen delignification stage followed by a chlorine dioxide(D), caustic extraction with peroxide (Ep), and then a chlorine dioxidestage. In another embodiment the pulp with an IV of 6.2 dl/g is treatedwith an enzyme after the oxygen delignification stage followed by achlorine dioxide (D) stage, caustic extraction with peroxide (Ep), achlorine dioxide stage and another enzyme stage, X, after bleaching.

The procedure for the preparation of the solution for the treatment isas follows. Table 1 gives the treatment conditions.

-   1. Makeup DI water to pH 7.-   2. Dilution of the enzyme (Biotouch C-700) with water of pH of 7 to    make a 1% solution. Dilution of the surfactant, (Tergitol), with    water of pH 7 to make a 1% solution.-   3. Add water with a pH 7 to the never dried control pulp (40 g. oven    dried basis) in sealed zipped plastic bags.-   4. Add 1% water cellulose solution or/and surfactant solution onto    the never dried (ND) pulp slurry so the final pulp consistency is    10%.-   5. Set the bag in a 70° C. water bath and let it sit for a retention    time of 1 hour.-   6. After one hour the treated pulp is washed with deionized water    and then the pulp is air dried for analysis.

TABLE 1 Pulp Treatment Conditions 1 kg 4.53 kg 1 kg each of C 700 C700/MT C 700/MT and 1 kg surfactant/ pulp pulp MT pulp Sample No. 1 2 3ND Pulp, g* 40 40 40 Cellulase, g .04 .4 .04 1% Cellulase soln, g 4 40 41% surfactant soln., g 4 Water, g, pH 7 356 320 352 Consistency, % 10 1010 *Never dried pulp, OD weight

The same procedure as used in Table 1was used to treat the same neverdried pulp with 0.23, 0.34, 0.45 and 2.27 kg/ton of C-700 to obtainsamples 4, 5, 6 and 7, respectively.

This same procedure with 1 kg/MT of Biotouch C-700 was used to treat 600gram (OD) pulp (never dried) to make “trial” pulp. The treated pulp andcontrol pulp had the properties listed in Table 2.

TABLE 2 Analytical Properties Of Cellulase Treated Peach ® Cellulase,Sample kg/MT pulp DP Cu No. IV, dl/g Control 608 0.6 3.2 4 0.23 570 0.93.0 5 0.34 561 1 2.95 6 0.45 551 1.1 2.9 1 0.9 532 1.3 2.8 Trial 0.9 5231.3 2.75 7 2.27 513 1.4 2.7  3* 0.9 513 1.4 2.7 2 4.54 456 2.2 2.4 *With0.9 kg surfactant/MT pulp (Tergitol)

The data indicates that cellulase treatment after bleaching can reduceviscosity; for example, at 0.9 kg/MT pulp the IV levels were reducedfrom 3.2 to 2.7 dl/g. High levels of enzyme have an adverse effect oncopper number and increase it to unacceptable levels.

Cellulase treated Peach® had a low viscosity and still sugar content asstarting control implying minimal yield loss The R₁₀ and R₁₈ aredecreased.

TABLE 3 Sugar and R₁₀, R₁₈ In Cellulase Treated Peach ® Sample Arabinan,% Galactan, % Glucan, % Xylan, % Mannan, % R_(10,) % R_(18,) % Control′0.45 0.24 82.19 7.15 5.01 84.1 87.0 (Peach ®) 1 0.3  0.24 83.24 6.855.30 76.6 84.5 2 0.37 0.24 84.53 6.82 5.30 73.8 84.1 3 0.41 0.26 82.867.42 5.71 76.4 84.6 4 0.32 0.20 82.30 7.42 5.25 5 0.31 0.19 87.86 7.185.15 6 0.31 0.20 83.00 7.29 5.21 7 0.30 0.19 82.69 7.154 5.18 Trial 0.310.19 84.14 7.13 4.99

R₁₀ refers to the residual undissolved material that is left afterattempting to dissolve the pulp in a 10% caustic solution. R₁₈ refers tothe residual amount of undissolved material left after attempting todissolve the pulp in an 18% caustic solution. Generally, in a 10%caustic solution, hemicellulose and chemically degraded short chaincellulose are dissolved and removed in solution. In contrast, generallyonly hemicellulose is dissolved and removed in an 18% causticsolution.Thus, the difference between the R₁₀ value and the R₁₈ valuerepresents the amount of chemically degraded short chained cellulosethat is present in the pulp sample. Providing a pulp having a relativelybroad molecular weight distribution of at least equal to or greater thanabout 2.8 is desirable from the standpoint of being able to providecustomers with pulp which may not require blending with pulps of othermolecular weight distribution to arrive at the desired composition.Sugar analysis was determined by the method described below.

TABLE 4 Metals (ppm) In Cellulase Treated Peach ® Control Sample 4 5 6 1Trial 7 2 (Peach ®) 3 Ca 60 50 60 50 60 50 30 60 40 Cu 0.2 0.2 0.3 0.40.2 0.2 0.3 0.3 0.2 Fe 4 4 2 5 2 3 3 3 3 Mg 20 10 20 10 10 10 <10 20 10Mn 2.7 2.8 2.8 2.5 2.4 2.6 1.8 3.4 2.2 Na 290 320 280 280 300 290 2501300 250

The data indicate that Cellulase treated pulps still have acceptabletransition metals (eg. copper, manganese and iron) and other metalscontent (metals such as calcium, sodium and magnesium) for lyocellmanufacture. Metal levels were determined by EPA 3050 and EPA 200.8M.

Both the control Peach(D and cellulose treated pulp (trial) weredissolved in lyocell solvent (NMMO (N-methylmolptioline N-oxide) in alab kneading machine at different concentrations and the viscosity, Pas,at different shear rates (zero shear, 1 and 10 l/s were measured atdifferent dissolution times (2, 4, and 6 hours) at differenttemperatures. The results are presented in Table 5.

TABLE 5 Rheology of Low DP pulp Compared with Peach ® Solution In NMMOViscosity Dope Kneading Visc. 80° C. (Pas) 100° C. (Pas) conc. timeshear rate, 1/s shear rate 1/s Pulp (%) (hr) 0 1 10 0 1 10 Control 8 2403 286 140 157 126 67 4 173 152 105 77 48 37 6 72 71 65 27 26 25 Trial8 2 168 137 84 78 62 42 4 160 135 84 58 53 39 6 84 79 64 29 27 24 Trial10 2 503 363 195 148 133 95 4 434 338 192 165 141 95 6 211 201 152 67 6456 Trial 12 2.5 1343 928 607 420 195 4.5 1169 837 379 320 201 6.5 670550 199 179 144

The low DP pulp (trial) had lower viscosity at all shear rates comparedwith Peach® (control). This indicates that higher throughput (higherconcentration at the same viscosity or higher throughput per hole perminute) for meltblowing is possible with lower DP pulp due to lowersolution viscosity.

Cellulase treatment can lower pulp viscosity. The treated pulp hasacceptable copper number and metal content for the lyocell process.Certain surfactants also help cellulase treatment. Treated pulp can havesimilar hemicellulose as a control (Peach®) pulp implying minimal yieldloss. The lower DP pulp has lower solution viscosity in NMMO, thus it ispossible to use lower DP pulp at higher throughput (higher concentrationor higher thoughtput per hole per minute during lyocell production) toimprove economics for lyocell production.

EXAMPLE 2

Weyerhaeuser Port Wentworth never dried pulp with bleaching sequence ofDEDED with a intrinsic viscosity of 7.1 or FB viscosity of 140 wastreated with 0.91 kg/MT or 0.9 lb/MT of Biotouch C-700 with the samecondition listed in Table 1 and the treated pulp had intrinsic viscosityof 5.9 or FB of 72.

EXAMPLE 3

Kamloops never dried pulp with a bleaching sequence of DEDED with aintrinsic viscosity of 3.7 or FB viscosity of 22 was treated with 0.91kg MT of Biotouch C-700 at the same condition as listed in Table 1 andthe treated pulp had intrinsic viscosity (IV) of 3.4 dl/g or FB of 19and a copper number of 0.9.

EXAMPLE 4

Weyerhaeuser Flint River Peach® (never dried) with an IV of 3.2 (OXDEpD)was treated with another Ep stage (2.0% NaOH, 3% H₂O₂, at 10%consistency, at 88° C. for 90 minutes). The treated sample has an IVviscosity of 2.6 and a copper number of 0.8. Part of the same samplefrom above treatment was dried and then treated with Biotouch C-700again (same condition as sample 1 in Table 1) to obtain a sample with anIV of 2.5 and copper number of 0.8. Part of the same sample above fromthe Ep stage was not dried and then treated with C-700 (same conditionas sample 1 in Table 1) again to obtain another samples having IV of 2.5and copper number of 0.8.

Never dried pulp after DEpD bleaching with different DP levels weretreated with 0.5% cellulase (Celluclast from Novozyme, on pulp) with orwithout surfactant (0.1% Tergitol on pulp);the conditions are shown inTable 6.

TABLE 6 Celluclast Treatment Condition Starting Treatment EnzymeTergitol Pulp water Time % % IV, slurry Sample pH hours (wt) (wt) DPdl/g pH Control 1 897 4.7 5.9 Control 2 782 4.1 5.2  8* 3.44 1.5 0.5 8504.5 5.3  9** 3.44 1.5 0.5 728 3.8 5 10* 3.44 1.5 0.5 0.1% 831 4.4 5.211** 3.44 1.5 0.5 0.1% 704 3.7 4.7 *from control 1; **from control 2

The analytical properties of the pulp are given in Table 7.

TABLE 7 Analytical Properties Of Cellulase Treated Pulp Mannan, SampleAlpha Hemi Cu No. R₁₀ R₁₈ Xylan, % % 8 85 15 0.6 84.7 87.2 6.22 4.86 984.8 15.2 0.8 84.1 87 6.21 5.09 10 84.6 15.4 0.7 84.1 86.9 6.45 4.91 1184.1 15.9 0.8 83.6 86.7 6.43 5.04 alpha cellulose was measured by TAPPImethod 203

EXAMPLE 6

In a representative example, Peach®, a never dried bleached kraftsouthern pine pulp, available from Weyerhaeuser, Federal Way, Wash., wastreated with cellulase (1% Ashland Biotouch 700) on air dry pulp weightwith the same condition as sample 1 in Table 1) to yield a pulp havingan average degree of polymerization of about 500 (IV of 2.63), ahemicellulose content of 12.0% by weight hemicellulose in pulp (6.8% and5.3% by weight xylan and mannan, respectively) and an R₁₀ and R₁₈, ofabout 76.6 and 84.5, respectively. The pulp was dissolved in NMMO(N-methyl morpholine N-oxide)/water mixture as follows. A 250 mL threenecked flask was charged with, for example, 66.4 g of 97% NMMO, 24.7 gof 50% NMMO, 10.4 g pulp, 0.1 g of propyl gallate. The flask wasimmersed in an oil bath at 105° C., a stirrer inserted and stirringcontinued for about 1 hr. A readily flowable dope resulted that wassuitable for spinning. The cellulose concentration in the dope was about12% by weight. The dope was extruded from a melt blowing die that had 3nozzles having an orifice diameter of 457 microns at a rate of 1.0gram/hole/minute. The orifices had a length/diameter ratio of 5. Thenozzle was maintained at a temperature of 95° C. The dope was extrudedinto an air gap 30 cm long before coagulation in water and collected ona screen as either continuous or discontinuous filaments depending ondope rheology and meltblown conditions. Air, at a temperature of 95° C.and a pressure of about 10 psi, was supplied to the head. Air pressuresof from 8 to 30 psi were used to achieve varying fibers diameters shownin Table 8.

FIG. 1 shows a longitudinal section of the fiber and indicates the fiberspun from a low DP pulp has a smooth surface.

TABLE 8 Lyocell Fiber Properties Control Meltblown lyocell 1 2 3 97%NMMO g 66.4 66.4 66.4 50% NMMO g 24.7 24.7 24.7 Propyl Gallate g 0.2 0.20.2 Pulp DP 532 532 532 Pulp g 10.5 10.5 10.5 Cellulose % 10.33 10.3310.33 Air Pressure (psi) 5 10.00 20.00 Diameter (micron) 20.0 15.2 9.1Birefringence 0.018 0.025 0.030 Xylan, % 5.0 5.2 5.1 Mannan, % 4.4 4.34.2

Sugar Analysis

This method is applicable for the preparation and analysis of pulp andwood samples for the determination of the amounts of the following pulpsugars: fucose, arabinose, galactose, rhamnose, glucose, xylose andmannose using high performance anion exchange chromatography and pulsedamperometric detection (HPAEC/PAD).

Summary of Method

Polymers of pulp sugars are converted to monomers by hydrolysis usingsulfuric acid. Samples are ground, weighed, hydrolyzed, diluted to200-mL final volume, filtered, diluted again (1.0 mL+8.0 mL H₂O) inpreparation for analysis by HPAEC/PAD.

Sampling, Sample Handling and Preservation

Wet samples are air-dried or oven-dried at 25±5° C.

Equipment Required

-   Autoclave, Market Forge, Model # STM-E, Serial # C-1808-   100×10 mL Polyvials, septa, caps, Dionex Cat #55058-   Gyrotory Water-Bath Shaker, Model G76 or some equivalent.-   Balance capable of weighing to ±0.01 mg, such as Mettler HL52    Analytical Balance.-   Intermediate Thomas-Wiley Laboratory Mill, 40 mesh screen.-   NAC 1506 vacuum oven or equivalent.-   0.45-μ GHP filters, Gelman type A/E, (4.7-cm glass fiber filter    discs, without organic binder)-   Heavy-walled test tubes with pouring lip, 2.5×20 cm.-   Comply SteriGage Steam Chemical Integrator-   GP 50 Dionex metal-free gradient pump with four solvent inlets-   Dionex ED 40 pulsed amperometric detector with gold working    electrode and solid state reference electrode-   Dionex autosampler AS 50 with a thermal compartment containing the    columns, the ED 40 cell and the injector loop-   Dionex PC10 Pneumatic Solvent Addition apparatus with 1-L plastic    bottle 3 2-L Dionex polyethylene solvent bottles with solvent outlet    and helium gas inlet caps-   CarboPac PA1 (Dionex P/N 035391) ion-exchange column, 4 mm×250 mm-   CarboPac PA1 guard column (Dionex P/N 043096), 4 mm×50 mm-   Millipore solvent filtration apparatus with Type HA 0.45u filters or    equivalent

Reagents Required

All references to H₂O is Millipore H₂O

72% Sulfuric Acid Solution (H2SO4)—Transfer 183 mL of water into a 2-LErlenmeyer flask. Pack the flask in ice in a Rubbermaid tub in a hoodand allow the flask to cool. Slowly and cautiously pour, with swirling,470 mL of 96.6% H₂SO₄ into the flask. Allow solution to cool. Carefullytransfer into the bottle holding 5-mL dispenser. Set dispenser for 1 mL.

J T Baker 50% sodium hydroxide solution, Cat. No. Baker 3727-01,[1310-73-2]Dionex sodium acetate, anhydrous (82.0±0.5 grams/1 L H₂0),Cat. No. 59326, [127-09-31.

Standards

Internal Standards

Fucose is used for the kraft and dissolving pulp samples.2-Deoxy-D-glucose is used for the wood pulp samples.

Fucose, internal standard. 12.00±0.005 g of Fucose, Sigma Cat. No. F2252, [2438-80-4], is dissolved in 200.0 mL H₂O giving a concentrationof 60.00±0.005 mg/mL. This standard is stored in the refrigerator.

2-Deoxy-D-glucose, internal standard. 12.00±0.005 g of2-Deoxy-D-glucose, Fluka Cat. No. 32948 g [101-77-9] is dissolved in200.0 mL H₂O giving a concentration of 60.00±0.005 mg/mL. This standardis stored in the refrigerator.

Kraft Pulp Stock Standard Solution

KRAFT PULP SUGAR STANDARD CONCENTRATIONS Sugar Manufacturer Purity g/200mL Arabinose Sigma 99% 0.070 Galactose Sigma 99% 0.060 Glucose Sigma 99%4.800 Xylose Sigma 99% 0.640 Mannose Sigma 99% 0.560

Kraft Pulp Working Solution

Weigh each sugar separately to 4 significant digits and transfer to thesame 200-mL volumetric flask. Dissolve sugars in a small amount ofwater. Take to volume with water, mix well, and transfer contents to twoclean, 4-oz. amber bottles. Label and store in the refrigerator. Makeworking standards as in the following table.

PULP SUGAR STANDARD CONCENTRATIONS FOR KRAFT PULPS mL/200 mL mL/200 mLmL/200 mL mL/200 mL mL/200 mL Fucose 0.70 1.40 2.10 2.80 3.50 Sugarmg/mL ug/mL ug/mL ug/mL ug/mL ug/mL Fucose 60.00 300.00 300.00 300.00300.00 300.00 Arabinose 0.36 1.2 2.5 3.8 5.00 6.508 Galactose 0.30 1.12.2 3.30 4.40 5.555 Glucose 24.0 84 168.0 252.0 336.0 420.7 Xylose 3.2011 22.0 33.80 45.00 56.05 Mannose 2.80 9.80 19.0 29.0 39.0 49.07

Dissolving Pulp Stock Standard Solution

DISSOLVING PULP SUGAR STANDARD CONCENTRATIONS Sugar Manufacturer Purityg/100 mL Glucose Sigma 99% 6.40 Xylose Sigma 99% 0.120 Mannose Sigma 99%0.080

Dissolving Pulp Working Solution

Weigh each sugar separately to 4 significant digits and transfer to thesame 200-mL volumetric flask. Dissolve sugars in a small amount ofwater. Take to volume with water, mix well, and transfer contents to twoclean, 4-oz. amber bottles. Label and store in the refrigerator. Makeworking standards as in the following table.

PULP SUGAR STANDARD CONCENTRATIONS FOR DISSOLVING PULPS mL/200 mL mL/200mL mL/200 mL mL/200 mL mL/200 mL Fucose 0.70 1.40 2.10 2.80 3.50 Sugarmg/mL ug/mL ug/mL ug/mL ug/mL ug/mL Fucose 60.00 300.00 300.00 300.00300.00 300.00 Glucose 64.64 226.24 452.48 678.72 904.96 1131.20 Xylose1.266 4.43 8.86 13.29 17.72 22.16 Mannose 0.8070 2.82 5.65 8.47 11.3014.12

Wood Pulp Stock Standard Solution

WOOD PULP SUGAR STANDARD CONCENTRATIONS Sugar Manufacturer Purity g/200mL Fucose Sigma 99% 12.00 Rhamnose Sigma 99% 0.0701

Dispense 1 mL of the fucose solution into a 200-mL flask and bring tofinal volume. Final concentration will be 0.3 mg/mL.

Wood Pulp Working Solution

Use the Kraft Pulp Stock solution and the fucose and rhamnose stocksolutions. Make working standards as in the following table.

PULP SUGAR STANDARD CONCENTRATIONS FOR KRAFT PULPS 2-Deoxy- mL/200 mLmL/200 mL mL/200 mL mL/200 mL mL/200 mL D-glucose 0.70 1.40 2.10 2.803.50 Sugar mg/mL ug/mL ug/mL ug/mL ug/mL ug/mL 2-DG 60.00 300.00 300.00300.00 300.00 300.00 Fucose 0.300 1.05 2.10 3.15 4.20 6.50 Arabinose0.36 1.2 2.5 3.8 5.00 6.508 Galactose 0.30 1.1 2.2 3.30 4.40 5.555Rhamnose 0.3500 1.225 2.450 3.675 4.900 6.125 Glucose 24.00 84 168.0252.0 336.0 420.7 Xylose 3.20 11 22.0 33.80 45.00 56.05 Mannose 2.809.80 19.0 29.0 39.0 49.07

Procedure

Sample Preparation

Grind 0.2±05 g sample with Wiley Mill 40 Mesh screen size. Transfer ˜200mg of sample into 40-mL Teflon container and cap. Dry overnight in thevacuum oven at 50° C. Add 1.0 mL 72% H₂SO₄ to test tube with theBrinklman. dispenser. Stir and crush with the rounded end of a glass orTeflon stirring rod for one minute. Turn on heat for Gyrotory Water-BathShaker. The settings are as follows:

-   Heat: High-   Control Thermostat: 7° C.-   Safety thermostat: 25° C.-   Speed: Off-   Shaker: Off

Place the test tube rack in gyrotory water-bath shaker. Stir each sample3 times, once between 20-40 min, again between 40-60 min, and againbetween 60-80 min. Remove the sample after 90 min. Dispense 1.00 mL ofinternal standard (Fucose) into Kraft samples.

Tightly cover samples and standard flasks with aluminum foil to be surethat the foil does not come off in the autoclave.

Place a Comply SteriGage Steam Chemical Integrator on the rack in theautoclave. Autoclave for 60 minutes at a pressure of 14-16 psi (95-105kPa) and temperature >260° F. (127° C.).

Remove the samples from the autoclave. Cool the samples. Transfersamples to the 200-mL volumetric flasks. Add 2-deoxy-D-glucose to woodsamples. Bring the flask to final volume with water.

For Kraft and Dissolving pulp samples:

Filter an aliquot of the sample through GHP 0.45 μ filter into a 16-mLamber vial.

For Wood pulp samples:

Allow particulates to settle. Draw off approximately 10 mL of samplefrom the top, trying not to disturb particles and filter the aliquot ofthe sample through GHP 0.45 μ filter into a 16-mL amber vial. Transferthe label from the volumetric flask to the vial. Add 1.00 mL aliquot ofthe filtered sample with to 8.0 mL of water in the Dionex vial. Samplesare run on the Dionex AS/500 system. See Chromatography procedure below.

Chromatography Procedure

Solvent Preparation

Solvent A is distilled and deionized water (18 meg-ohm), sparged withhelium while stirring for a minimum of 20 minutes, before installingunder a blanket of helium, which is to be maintained regardless ofwhether the system is on or off. Solvent B is 400 mM NaOH. Fill SolventB bottle to mark with water and sparge with helium while stirring for 20minutes. Add appropriate amount of 50% NaOH.

(50.0 g NaOH/100 g solution)*(1 mol NaOH/40.0 g NaOH)*(1.53 g solution/1mL solution)*(1000 mL solution/1 L solution)=19.1 M NaOH in thecontainer of 50/50 w/w NaOH.

-   0.400 M NaOH*(1000 mL H₂O/19.1 NaOH)=20.8 mL NaOH-   Round 20.8 mL down for convenience:-   19.1 M*(20.0 mL×mL)=0.400 M NaOH-   x mL=956 mL

Solvent D is 200 mM sodium acetate. Using 18 meg-ohm water, addapproximately 450 mL deionized water to the Dionex sodium acetatecontainer. Replace the top and shake until the contents are completelydissolved. Transfer the sodium acetate solution to a 1-L volumetricflask. Rinse the 500-mL sodium acetate container with approximately 100mL water, transferring the rinse water into the volumetric flask. Repeatrinse twice. After the rinse, fill the contents of the volumetric flaskto the 1-L mark with water. Thoroughly mix the eluent solution. Measure360±10 mL into a 2-L graduated cylinder. Bring to 1800±10 mL. Filterthis into a 2000-mL sidearm flask using the Millipore filtrationapparatus with a 0.45 pm, Type HA membrane. Add this to the solvent Dbottle and sparge with helium while stirring for 20 minutes.

The post column addition solvent is 300 mM NaOH. This is addedpostcolumn to enable the detection of sugars as anions at pH >12.3.Transfer 15±0.5 mL of 50% NaOH to a graduated cylinder and bring to960±10 mL in water.

(50.0 g NaOH/100 g Solution)*(1 mol NaOH/40.0 g NaOH)*(1.53 g Solution/1mL Solution) (1000 mL Solution/1 L solution)=19.1 M NaOH in thecontainer of 50/50 w/w NaOH.

-   0300 M NaOH*(1000 ml H2O/19.1 M NaOH)=15.7 mL NaOH-   Round 15.7 mL down:-   19.1M*(15.0 mL/x mL)=0.300 M NaOH-   x mL=956 mL-   (Round 956 mL to 960 mL. As the pH value in the area of 0.300 M NaOH    is steady, an exact 956 mL of water is not necessary.)-   Set up the AS 50 schedule.-   Injection volume is 5 uL for all samples, injection type is “Full”,    cut volume is 10 uL, syringe speed is 3, all samples and standards    are of Sample Type “Sample”. Weight and Int. Std. values are all set    equal to 1.-   Run the five standards at the beginning of the run.-   After the last sample is run, run the mid-level standard again as a    continuing calibration verification-   Run the control sample at any sample spot between the beginning and    ending standard runs.-   Run the samples.

Calculations

-   Calculations for Weight Percent of the Pulp Sugars

${{Normalized}\mspace{14mu} {area}\mspace{14mu} {for}\mspace{14mu} {sugar}} = \frac{\left( {{Area}\mspace{14mu} {sugar}} \right)*\left( {µ\; g\text{/}{mL}\mspace{14mu} {fucose}} \right)}{\left( {{Area}\mspace{14mu} {Fucose}} \right)}$${IS}\mspace{14mu} {Corrected}\mspace{14mu} {sugar}\mspace{14mu} {amount}\mspace{14mu} \left( {{{µg}\text{/}{mL}} = {{\frac{\left( {\left( {{Normalized}\mspace{14mu} {area}\mspace{14mu} {for}\mspace{14mu} {sugar}} \right) - ({intercept})} \right)}{({slope})}{Monomer}\mspace{14mu} {Sugar}\mspace{14mu} {Weight}\mspace{14mu} \%} = {\frac{{IS} - {{Corrected}\mspace{14mu} {sugar}\mspace{14mu} {amt}\mspace{14mu} \left( {µ\; g\text{/}{mL}} \right)}}{{Sample}\mspace{14mu} {{wt}.\; ({mg})}}*20}}} \right.$

Example for arabinose:

${{Monomer}\mspace{14mu} {Sugar}\mspace{14mu} {Weight}\mspace{14mu} \%} = {{\frac{0.15\mspace{14mu} {µg}\text{/}{mL}\mspace{14mu} {arabinose}}{70.71\mspace{14mu} {mg}\mspace{14mu} {arabinose}}*20} = {0.043\%}}$Polymer  Weight  % = (Weight  %  of  Sample  sugar) * (0.88)

Example for arabinan:

Polymer Sugar Weight %=(0.043 wt %)*(0.88)=0.038 Weight Note: Xylose andarabinose amounts are corrected by 88% and fucose, galactose, rhamnose,glucose, and mannose are corrected by 90%. Report results as percentsugars on an oven-dried basis.

1. A method for making a lyocell pulp comprising the steps of providingan unbleached pulp; wherein said pulp has a IV of from 10 to 5 dl/g;contacting said pulp in a bleaching sequence; wherein said bleachsequence has at least one stage of an enzyme treatment; wherein saidbleach sequence having at least one enzyme treatment reduces said pulpby 8 to 2 IV units; and wherein said bleached pulp is suitable forlyocell manufacture.
 2. The method of claim 1 wherein the enzymetreatment is immediately after the oxygen delignification stage.
 3. Themethod of claim 1 wherein the enzyme treatment is after the lastbleaching stage.
 4. The method of claim 1 wherein the enzyme treatmentis immediately after the oxygen delignification stage and after the lastbleaching stage.
 5. The method of claim 1 wherein the enzyme is added at0.045 to 4.5 kg/MT pulp.
 6. The method of claim 1 wherein the enzyme isadded at 0.136 to 3.27 kg/MT pulp.
 7. The method of claim 1 wherein theenzyme is added at 0.227 to 1.3 kg/MT pulp.
 8. The method of claim 1wherein the IV is reduced to 2 to 4 IV units
 9. The method of claim 1wherein the IV is reduced to 2.5 to 3.5 IV units.
 10. The method ofclaim 1 wherein the pH is adjusted after the oxygen delignificationstage and before the bleaching stage.
 11. The method of claim 10 whereinthe pH is adjusted in the range of a pH of 3 to a pH of
 10. 12. Themethod of claim 1 wherein the pH is adjusted after the last bleachingstage.
 13. The method of claim 12 wherein the pH is adjusted in therange from a pH of 3 to a pH of
 10. 14. The method as in any one ofclaims 10 or 12 wherein the pH is adjusted with carbon dioxide.
 15. Themethod as in any one of claims 10 or 12 wherein the pH is adjusted witha mineral acid.
 16. The method as in any one of claims 10 or 12 whereinthe pH is adjusted with an organic acid.
 17. The method of claim 1wherein the enzyme is selected from the group consisting of xylanases,cellulases, hemicellulases, peroxidases, mannases, laccases, lipases andcombinations thereof.